Reference | Elviss2009 (20030)

Two flocks (1 and 3), which were broiler and layer birds, respectively, were treated on the farm (see below for treatment details). Flock 1 comprised 5100 free-range broilers sampled at 50 days old and Flock 3 was a barn-reared layer flock of 5600 birds sampled at 119 days old. The remaining two flocks (2 and 4) were broiler birds removed from commercial poultry flocks reared for human consumption. These birds were housed at the School of Clinical Veterinary Science, University of Bristol. These birds were housed at a stocking density of 12.6 kg/m2 to meet the UK Home Office requirements. All animal experiments were conducted according to the requirements of the Animals (Scientific Procedures) Act 1986 and were approved by the local ethical review committee. Each group of birds was housed independently in separate rooms. The University of Bristol’s Animal Services Units biosecurity protocol was followed. This included the use of protective clothing which was worn throughout husbandry and sampling. Separate protectiveclothing and footwear was worn for each room and disinfectant bootdip used upon every entry and exit of the rooms. The footwear worn was dedicated to the animal house and had not previouslybeen worn outside. All birds were weighed before therapy commenced. Food consumption was not measured; however, animal care staff confirmed that the animals fed normally. The treatment histories of the birds were obtained and none had previous exposure to ampicillin or other antimicrobials. Flocks 1 and 3 were given amoxicillin therapy [15 mg/kg/day amoxicillin (Vetremox; Alpharma Animal Health Ltd, Hampshire, UK) for 3 days] administered in the drinking water as prescribed by the veterinarian (this therapy can be prescribed for a range of poultry diseases including pasteurellosis and colibacilliosis). Flocks 2 and 4 were treated with amoxicillin under experimental conditions. Flock 2 consisted of 20 birds brought on-site at 21 days of age from a commercial free-range organic broiler flock comprising 7500 birds in September 2004. The birds received a therapeutic dose (15 mg/kg/day for 3 days) of amoxicillin (Amoxinsol 100; Ve´toquinol UK Ltd, Buckingham, UK) administered in the drinking water. Flock 4 comprised 28 birds brought on-site in October 2005 that were purchased at 22 days of age from a commercial free-range broiler flock consisting of 6300 birds. Fourteen birds received amoxicillin therapy as described above. A control group of 14 birds, housed independently, remained untreated throughout. The four farms from which the flocks were sourced were not in close geographical proximity.

Twenty freshly voided faecal samples were collected before, during and then weekly for up to 4 weeks post-treatment. Flock 1 was only sampled up to 1 week post-treatment, as the birds were sent for slaughter at that time. These flocks were from independent geographically distinct farms. For flocks 2 and 4, twenty freshly voided faecal samples were collected pre-, during and then weekly for up to 4 weeks post-therapy. All samples were transported to the laboratory within 3 h of collection.

AST Method: None

Reference explicitly reports AST breakpoints: True

Reference reports using a MIC table: True